DUNEDIN TO MOSGIEL.

DUPLICATION OF THE RAILWAY LINE. CAVERSHAM TUNNEL PIERCED. An impDrta'it step in the duplication i-f the railwiu lina from Dunedin to Mosgiel \va~ eomplctc-d on Ihc 21st, when tho piercing of tha i L-w Ca\ercham tunrel fio.n end to end w<".;> uccompl. e hrd Th.> l:oadings fiom from- each side met at noon. auJ wi'li the breaking- down of the imsrvening wall of sandstone, the driving of the longest tunnel but on? in the Dominion uas at an end. The commec?mer;t of this imnoitant work date« Lack to No\ amber of 1907, since when work ha< beenb c en carried on steadily, never more than two shift-, and sometimes one. beine engaged. Ihe total le-rrgth of the tunnel is 71 chains. A<s stated above, it is the loner^st tunnel hut one in- tho Dominion th© Ljttelton tuirnel claimipir that distinction. By way of comparison, it might be mentioned that tbo Caversham tnnn-al ir us? at present is about 43 ehai'.s long-, and that at Deboiab Bay abour 66 chains in length. One- feature that distinguishes tho i.ew tuiTiiel from all others is that it is the first double tunnel to be construiotcd in Xiew Zwaiand. Thenature of the materiaL that had to be driv3n through was Caversham sarrdstone. a similar formation to that met with mi the tun.iel at present in v.so. In all. about 66,000 cubic yards of sar.dstorie have been taken out The northern end is 52ft and the southern end 40ft below th? corresponding pi"tk of ihe eld tunnel, while the greater d-e'^rh below ihe surface of tlte big h'h undor which it i« driven is 352 ft. The grade i« one in 132. as against one in 50 in *K° othjr tunnel and there is a curve oE 25 chains radius towards the CatrleyaivU end. Otherwise, tho tunnel run.- straight throughout Tho width acros- the mouth of the tunnel i= 25ft 7in. and th? height 19ft 6ir. gi\ing it roughly t'irta times eh : area of a single tunnel. Practically all tha* now leniains to be dc le is to tak^ cm Hi> bottom to the leciuirpd lc\e! o\'-r a di=tanc of eight rhain^. Tlio for.natio'.i -> of a good standing lvatuie throughout, «nd excepting for about four cv- five <-hams .-.•t tlio southern end. which will require to be lined, the tunnel will remain iir >'to natmal stat-e. In about two months frora the present time it will have beon competed in all detail It will hold a double ss<t of rails, in kee-piirg with the duplicatio.i and the expei ier.ee, should it ovoi' b? n\et. of trains pacing each other inskb th-e tunnel should certainly be a ro\el one. The coh-truction of the new CattleyarcU , Station buildingh. the first stopping place for trains past the sonth end of the Caversham tunnel, i« JU st about lo be put in hand. The nsw station will be 10 chains routh of the present . one. The platfon.i frontagi"! are already in position and the laj mg- down of the »icliit^% will be put- in Hand in two or three day*. Everything w ill be in readiness at this point by the time that the line has been extended through th? new tunnel, and the public may anticipate ridiriK on the oveihcad railway from Dunedin to Cattkyaick, and vies' \er,a, , early in- tho new year. I